1. Field of the Invention
The present invention relates to a lighting apparatus, and more particularly, to a lighting apparatus capable of stably performing dimming control on a lamp implemented with light emitting diodes.
2. Description of the Related Art
According to the recent trend, more and more lighting apparatuses have employed light emitting diodes (hereafter, referred to as LEDs) as a light source. The LEDs may be implemented to have a longer lifespan, lower power consumption, and higher brightness than incandescent lamps and fluorescent lamps.
Examples of the lighting apparatuses may include indoor lights, streetlamps or the like. Recently, lighting apparatuses employing LEDs have been developed and commercialized as indoor lamps, security lamps, or streetlamps.
In general, conventional LED lighting apparatuses have a configuration in which normal AC power is supplied through a switching mode power supply (hereafter, referred to as “SMPS”) module.
An example of the conventional LED lighting apparatuses has been disclosed in Korean Patent No. 10-1164631, and has a configuration in which normal AC power is supplied to LEDs through an SMPS module and a driving circuit.
The conventional LED lighting apparatus may additionally include a sensor board having a sensor to sense illuminance or human body, in order to control dimming or switching. In this case, the LED lighting apparatus is configured to supply power to the sensor board through the SMPS module.
However, since the above-described conventional LED lighting apparatus includes the SMPS module for supplying power to the LED lamps and the driving circuit for driving the LED lamps through a current driving method, the configuration of the conventional LED lighting apparatus is relatively complex.
In the convention LED lighting apparatus, the SMPS module is designed to have a power efficiency of about 90%, and the driving circuit is also designed to have a power efficiency of about 90%. As a result, the entire power efficiency of the LED lighting apparatus is set to about 81%. As such, the conventional LED lighting apparatus has such a problem that the complex configuration thereof reduces the entire power efficiency.
The LED lighting apparatus may additionally include peripheral circuit modules such as a sensor board. In this case, most of power may be consumed by the driving circuit to drive the LEDs.
Thus, the problem that the power efficiency of the conventional LED lighting apparatus is reduced may also occur in the peripheral circuit modules which are additionally provided, thereby reducing the power efficiency of the peripheral circuit modules.
Furthermore, the conventional LED lighting apparatus may perform dimming control through a constant current control method.
The conventional LED lighting apparatus may include a dimming control processor for the dimming control. The dimming control processor requires a predetermined level or more of operating voltage for constant current control.
The operating voltage may be provided through a driving voltage applied to LED lamps.
However, when light output is controlled at such a low level as in a dimming-off state, the driving voltage provided to the LED lamps may not maintain a level required for generating an operating voltage requested by the dimming control processor.
As described above, when the driving voltage becomes lower than the level required for generating the operating voltage requested by the dimming control processor, the conventional lighting apparatus cannot stably perform dimming control.